Telephone system



Filed July 1o, i951 3 Sheets-Sheet l Inventar Y Char-les 1131-.: :ks

Oct. 10, 1933. Q R. BROOKS 1,929,474

TELEPHONE SYSTEM Filed 4July 10. 1931 3 Sheets-Sheet 2 ,QM/6. GEN

Inu' an'm" Charles R. Braak;

Oct. 10, 1933. c. R. BRooKs 1,929,474

TELEPHONE SYSTEM Filed July 10, 19.31 3 Sheets-Sheet 3 Patented Oct. 10, 1933 UNITED STATES TELEPHONE SYSTEM Charles R. Brooks, Chicago, Ill., assignor, by

mesne assignments, to Associated Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Application July 10, 1931. Serial No.V 549,967

35 Claims.

The present invention relates toV telephone systems in general, but is particularly concerned with paystation circuits and trunk circuits used to give toll service to paystations and to regular subscribers, or local, stations.

The principal object of this invention is to produce an automatic telephone system in which toll service can be given to both paystations and local stations by means of equipment which is common to both types of stations and which will meet all requirements of standard practice.

Another object is to provide a paystation circuit in which ordinary'types'of relays and not polarized relays are used for controlling the distribution of coins. The manner in which this object is accomplished by the use of electronic Valves of the copper-oxide type constitutes one of the features of this invention.

It is now the common practice in automatic telephone systems to segregate the paystations from the local stations as regards trunks accessible thereto for the extension of calls anduto' provide those trunks accessible to the paystations for toll service with what are commonly known as paystation repeaters. The present invention contemplates the use of a trunk which is capable of use by both paystations and local stations and which does not require a paystation repeater. The features of this trunk circuit and other features and objects of the invention not specically mentioned at this time will be apparent from the detailed description, which follows, when studied in conjunction with the accompanying drawings comprising Figs. l to 3, inclusive, which by means of appropriate symbols diagrammatically depict the system of the present invention.

In Fig. 1 are shown two stations, the paystation A and the local station A'. These stations are provided with the usual automatic substation instrumentalities. Paystation A, in addition to these, is provided with a coin-collectingand refunding apparatus which includes a collect magnet 12 and a refund magnet 13 for controlling the coin distributing mechanism in its functions. Coin-collect mechanism is well known, but in the instant case coin-collect mechanism is employed which is similar to that shown and described in the co-pending application of Hans Sengebusch, Serial No. 546,968, filed June 26, 1931.

Each substation is provided with an individual line switch, such as LS, which is of the wellknown rotary type of switch, the wipers of which move in a forward direction only and have no normal position, remaining in used.

These line switches have access to selector switches, such asS, which are or" the well-known Strowger type of two-directional-motion switch. In the present system it is assumed that the selector switches have access to connector switches.l for the completion of local callsand access'to trunks, such as that comprising 'conductors 43 to 45, inclusive, regardless of the type of calling substation, for calls to, a toll operator. j

, The combined line and recording trunk of this inventionthat is, the trunk'common to both paystations and localV stationsis shown in Fig. 2. This trunkte'rminates'in a jack in a 7() toll operators position, Fig. 3. The'toll operators position is represented by a 'skeleton cord circuitO. K

1t willbe assumed that a subscriber at paystation A desires to call and converse with the subscriber at station A. This is termed a local paystation call and usually requires the payment ofl a single five-cent coin. "It is the generalpractice to arrange an automatic'telephone system for what is termed post-pay service. Under these conditions, a paystation subscriber can obtain a connection in a local call without first depositing a coin or token, but cannot converse with the called partyuntil after a coin has been deposited. This class of service is usually desirable, since it permits such calls' as re, police, other emergency calls, and toll calls to be made without a coin rs't having to be deposited. K

When pre-'pay service is used, a short circuit is usually placed around the impulse springs of the calling device of an automatic paystation, which circuit is opened only by the depositing of a coin, thus preventing the extension of a call until acoin is deposited. In the present illustration it will be assumed that the paystation equipment is arranged for post-pay service. Therefore, when a subscriber at paystation A desires to make a call, he will remove the receiver from the switchhook and proceed to dial the desired number. The removal (of the receiver at `10o paystation A causes contact 2 of the contacts controlled by the switchhook to move out of engagement with contact 3 and into engagement with contact 1, and causes contact 4 to engage, its make contact. Engagement of contacts 1 and 2 completes the loop circuit for the line relay of the line switch LS over the loop circuit starting with ground throughresting contacts ofvthevcutoff relay (not shown) of the line switch, positive line conductor 16, impulse contacts 32 of'calling theV position last device C, copper-oxide valve 34, primary winding of induction coil relay 17, normally closed contacts controlled by armature 20 of relay 17, transmittei- T, switchhook contacts 1, 2, negative line conductor 15, to battery through resting contacts of the cut-off relay and the Winding of the line relay (not shown) of the line switch. The line switch LS thereupon operates to select a trunk leading to an idle selecting switch which, it will be assumed, is selector switch S. The calling subscriber now dials the rst digit of the desired number. The selector S responds in the wellknown manner to the impulses'generated by the calling device C to elevate its wipers to the appropriate level and then automatically rotate them to select a trunk to an idle connector switch. It will be assumed that the trunk selected is that which is represented in the drawings by the bank contacts 46 to 48, inclusive. The connector switch hasl not been shown, since connectors of the Strowger type are well known and their operation is well understood.

The subscriber now dials the last two digits of the desired number, whereupon the connector selects the desired called line and, if the line is idle, applies' ringing current thereto to signal the called subscriber. When the called subscriber answers, the back bridge relay of the connector reverses the battery feed to the calling line in the well-known manner.

When this reversal occurs, the normally positive line conductor 16 becomes the negative conductor and the normally negative conductor 15 becomes the positive conductor. Current flowing in this reversed direction through the paystation circuit cannot pass through the 'copperoxide rectifier 84 and therefore flows ythrough the winding of relay 2l, the vdirection of current flow through the electronic valves being indicated by the plus and minus signs. When this occurs, relay 21 begins to energizeand to attract its armatures 22 to 26,'inclusive. Theseh armatures are so adjusted that armature engages its con- 'tact a considerable time before the other armatures complete, their strokes. Engagement of armature 25 and its make Contact short circuits the winding of relay 2l by way of coin contacts 9, 8 and conductor 3l. Relay 2l thereupon deenergizes and restores itsV armatures before any of them, except armature 25, has completed its stroke. At armature 25 the short circuit of relay 21 is removed andthe relay again commences to energize and -attract its armatures. This cycle of operation is continously repeated anda tone signal is generated thereby in the line circuit, which tone is loud enough to prevent conversation taking place.

The called subscriber can cause the tone to cease by depositing a coin in the coin collector, the coin when deposited striking the lever 10, moving the latch 11 to the right where it catches on the armature 14 of the coin control magnets. Movement of latch 11 moves coin contacts 8 and 6 to the right. This opens the short circuit of relay 21 at contacts 9, 8, allowing that relay to completely energize, and at contacts 6 5 prepares the circuit of collect magnet 12 in order to vcollect the deposited coin when the conversation is terminated.

Relays 21 and 27 are arranged as mechanically interlocking relays whosearmatures 22 and 28 maintain either one or the other in the operated position. As diagrammatically represented in Fig. 1, the armature 22v of relay 21 is in such position when thev relay 21 Vis deenergized as to landvcloses switchhook contacts 2 3.

`to permit relay 21 to'restore.

prevent the armature 28 of relay 27 from restoring to normal position after the circuit of relay 27 is opened. When relay 21 completely enerzes and completely attracts its armature 22, the armature 28 of relay 27 retracts and assumes a position back of the armature 22 of relay 21 so as to prevent the retraction of armature 22 when relay 21 deenergizes. Preventing the armature 22 from retracting maintains armatures 23 to 26, inclusive, in engagement with their make contacts. When relay 27 energizes, it attracts its armature 28 which frees the armature 22, allowing that armature and consequently the other armatures of relay 2l to restore. Armature 22 thereupon assumes the position shown in the drawings and when the relay 27 deenergizes the armature 28 thereof is prevented from reti-acting as are also armatures 29 and 30. Thus in the normal condition of the apparatus, although the relay 27 is not energized, its armatures 28, 29, and 3() are in their attracted positions.

Therefore, when the relay 21 energizes completely after'the short circuit about its winding has been opened at coin contacts 9 8, the armature 28 of relay 27 retracts and assumes the position to prevent restoration of the armatures of relay 21. Upon completely energizing, relay 21 at its armature 23 and make contact prepares a holding circuit for the coin control magnets, at its armature 24 and make contact prepares a circuit for the upper winding of relay 27, and at its armature 26 and make contact prepares an auxiliary circuit for the collect magnet l2. When the armature 29 o relay 27 retracted following the complete energization of relay 2l, it engaged its resting contact and shortcircuited both the winding of relay 2l and the electronic valve 3'4. This removes the winding of relay 21 and the valve from the talking circuit to reduce the impedance thereof. Although the winding of relay 21 is short circuited, its armatures cannot retract because of the retracted position of armature 28 of relay 27 as explained.

Conversation between the two subscribers may now take place and when nished will be followed by the replacement of the receivers. Replacement of receiver R opens switchhook contacts 1 2 When the current flow in the calling line is restored to normal by the connector, the current flows from the positive conductor 16 over conductor 31, through coin contacts 6 5, winding of collect magnet 12, make contact and armature 26 of relay 21, resting contact and armature 19 of relay 17, electronic valve 37, by way of switchhook contacts 3 2, and over the negative line conductor 15. The collect magnet 12 thereupon operates and collects the deposited coin, also operating the armature 14 which releases the latch l1 and restores the coin contacts vto normal. Attraction of armature 14 tilts the mercury switch M, thereby closing its contacts, which operation is without any effect at this time.

Restoration of coin contact 6 opens the circuit of the collect magnet 12 and at contact 7 completes the following circuit for relay 27; positive conductor 16, conductor 31, coin contacts 7 6, armature 24 and make contact of relay 2l, upper winding of relayv 2'?, electronic valve 37, to negative line conductor 16 by way of switchhook contacts 3 2. Relay 27 operates in thiscircuit and completely attracts its armatures, thereby at armature 28 releasing armature 22 of relayl 21 Restoration of relay 2l at its armature 24 opens the circuit of relay 27 'which thereupon deenergizes. The armatures 28, 29, and 39 are held mechanically in their attracted positions by armature 22 of relay 21.

Opening of the circuit of the upper winding of relay 27 at armature 24 of relay 21 also opens the loop circuit to the line relay of the connector, thereby permitting the connector to release and to release the selector S and line switch LS. The apparatus at pay station A is now in the condition shown in the drawings and in readiness for another call.

Assuming that the subscriber of substation A had inadvertently deposited a coin before removing the receiver from the switchhook, this coin would have been immediately refunded because with the coin contact 6 in engagement with contact 5, caused by the depositing of the coin, and the switchhook contacts in their normal position, the following circuit would be completed for the refund magnet 13: ground on conductor 16 from the line switch, conductor 31, coin contacts 6-5, winding of refund magnet 13, resting Contact and armature 26 of relay 21, resting contact and armature 19 of relay 17, electronic valve 37, switchhook contacts 3 2, and back to negative battery in the line switch over the line conductor 15. The refund magnet 13 will thereupon operate to refund the deposited coin and restore the coin contacts. Should the subscriber at paystation A deposit a coin after removing the receiver from the switchhook but before dialling, the relay 2l would not operate as described to set up a tone in the calling line when the connector reverses battery upon the response of the called party because the short circuit of relay 21 established under the previous condition at armature 25 and its make contact of that relay would be open at coin contacts 9-8.

Under these conditions, relay 21 will completelyy energize immediately and mechanically lock itself by restoring the relay 27 which at its armature 29 and resting contact would again remove the electronic valve 34 and the winding of relay 21 from the talking circuit, leaving the transmitter connected through a low resistance path.

From the foregoing it will be appreciated that paystation coin-collecting-and-refunding apparatus has been controlled in a local connection through collect and refund magnets without the usual polarized relay by the use of electronic valves. 1t will also be appreciated that by the use of these valves the flow of current through the paystation apparatus has been directed to prevent conversation between a paystation subscriber and any other subs riber in a local connection until a coin has been deposited, even though the connection has already been established.

When the subscriber at the paystation A desires to make a toll call, he will, after removing his receiver from the switchliook, operate his calling device in accordance with the proper number to obtain connection to the toll operator. It is immaterial in this case whether or not the subscriber deposits a coin after removing his receiver but before operating his calling device. For the sake of description, it will be assumed that the subscriber deposited a coin before attempting to establish connection to the toll operator. This depositing of the coin operates the coin contacts which are then locked in their operated positions, as before explained.

It will also be assumed that, after the line switch LS has selected the selector S and the selector S has been operated in accordance with the number necessary to obtain connection with the tollV operator, the wipers 38', 39', and the test wiper of the selector come to restin engagement with contacts 40 to 42,V inclusive, of the trunk 43-45, leading to the toll operators position. When this occurs, the selector functions in the usual manner to extend the calling loop to this trunk circuit, whereupon the relay 100, Fig. 2, operates over this loop circuit which extends from lground through the lower winding of relay 100, lower left-hand winding of repeating coil I, normally closed contacts controlled by armature 160 of relay 156, resting contact and armature 155 of relay 153, resting contactand armature 121 of relay 113, positive trunk conductor 45, bank contact 42 and wiper 39 of selector S, lower talking conductor through the selector S, wiper 39' of line switch LS, lower talking conductor through the line switch, positive line conductor 16, impulse contacts 32 of calling device C, electronic valve 34, primary windings of induction coil relay 17, normally closed contacts controlled by armature 20 of relay 17, transmitter T, switchhook contacts 1--2, negative line conductor 15, through the'line switch to wiper 38, negativetalking conductor through the selector S, line wiper 3SV bank contacts 40, negative trunk lconductor 43,

armature 114 and resting contact of relay 113,

yarmature'154 and resting contact of relay trolled by armature 134 of relay 132, armature 102 and make contact of relay 190, resting contact and armature 119 of relay 113, and winding of relayk 122 to battery. Relay 122 operates in this circuit and at armature 125 and make contact extends its energizing ground by way of resting contact and armature 111 of relay 107 to battery Vthrough winding of relay 103. At armature 123 relay 122 extends holding ground back to the selector S over release trunk conductor 44, and at armature 124 starts the contact of this armature vibrating. The make contact of armature 124 is provided with a weight which causes the Contact to vibrate when it is struck by this armature 124 upon the attraction thereof, which contact vibrates for a considerable length of time before coming to rest in engagement with armature 124, thereby delaying the closing of the circuit therethrough.

Relay V103 operates and attracts its armatures 104 to'196, inclusive, performing no particular function at this time at its armature 104 and 105 but at armature 106 completing the circuit of Arelay 176 from grounded armature 136 and resting contact of relay 132, armature 112 and resting contact of relay 107, armature 106 and make contact, and winding of relay 176 to battery.

Relay 176 is shown diagrammatically as provided with two piles of carbon disks 179 and 180 whichv are compressed by a plunger 178 attached to the armature 177 when armature 177 `is attracted upon the energization of relay '176. These two piles of carbon 179 and 180 are serially connected in a bridge circuit across the trunk conductors 43 and 45 and when the disks are in the uncompressed condition they present a bridge circuit of more than 20,006 ohms. When the disks are compressed by the operation of relay 176, this resistanceV is gradually reduced to approximately 10 ohms.

Therefore, when relay 176 operates upon the closure of its circuit by relay 103, a low-resistance short circuit is placed across the trunk conductors 43 and 45, thereby cutting off the current 110W over the line to the paystation A.

The vibrating contact of armature 124 of relay 122 is so timed that it comes to rest immediately after relay 176 has placed the short circuit on the calling loop. When this occurs, the circuit of relay 113 is completed in parallel with that of relay 122 by way of normally closed contacts controlled by armature 120 of relay 113 and resting Contact and armature 143 of relay 138. Relay 113 operates in this circuit and at its armature 120 and make contact locks itself to ground by Way of conductor 181 and resting contact and armature 136 of relay 132. At its armatures 114 and 121 relay 113 disconnects the windings of relay 100 from conductors 43 and 45 and connects the conductors respectively to direct ground and to positive 110-volt current through make contacts of armature 121, armature 137 and resting contact of relay 132, Winding of relay 144, resistance lamp L2, to the 110-volt current source. rThis 110-volt current does not 110W over the calling loop because of the 10W-resistance short circuit through the carbon piles of relay 176.

Relay 144 operates from this 110-volt current and at its armature 145 opens a point in the circuit of relay 147.

Relay 113 at its armature 115 prepares a point in the circuit of relay 147, at its armature 116 connects ground to conductor 44, operates its armature 117 Without any eiect at this time, and at its armature 119 opens the energizing circuits of relays 122 and 103. These relays thereupon release slowly because of the copper slugs on their cores and also in the Vcase oi relay 103 because of the copper sleeve on its core.

Relay 103 slowly releases relay 176 which also releases slowly because of the copper slug on its core. Relay 176, slow-releasing, gradually decreases the pressure on the carbon piles, thereby gradually increasing the resistance of the short circuit until the maximum of approximately 26,600 ohms is reached. This high resistance no longer short circuits the 110-Volt current from the calling loop and the current therefore flows over conductor 45, through the selector and line switch, through the primary Winding of induction coil relay 17, and back through the line switch and selector. and over conductor 43 to ground at armature 114 and its make contact. The paystation apparatus thereupon functions to refund the deposited coin and to increase the resitsance of the loop circuit, as will be explained later.

When the resistance of the lcop circuit is increased, relay 144, being marginal,V deenergizes and at its armature 145 and resting contact completes the following circuit: ground, armature 140 and resting contact, normally closed contacts controlled by armature 134, resting contact and armature 164 of relay 103, resting contact and armature 108 of relay 107, make contact vand armature 115 of relay 113, resting contact and armature 133 of relay 132, resting contact and armature 145 of relay 144, normally closed contacts controlled by armature 149 of relay 147, and Winding or relay 147 to battery. Relay 147 operates in this circuit, at its armature 149 and make contact locks itself to ground on conductor 44 supplied through make contact and armature 116 of relay 113, at armature 151 and make contact prepares a circuit for relay 156, and at, armature 152 prepares a circuit for the paystation lamp L, Fig. 3.

Relay 126 operates When its circuit is closed by relay 113 and at its armature 127, starts its contact vibrating. This Contact is similar to that With which relay 122 is provided and comes to rest an interval after relay 176 has restored, to complete the circuit of relay 107 from ground by Way of resting contact and armature 136. Relay 107 thereupon attracts its armatures 108 to 112, inclusive, at armature 108 opening a point in the energizing circuit of relay 147, at armature 109 preparing the circuit or" relay 128, at armature 110 completing a second energizing circuit for relay 122 from ground on conductor 181, make contact and armature 110, make contact and armature 119, and Winding of relay 122 to battery, and at armature 111 and make contact connecting Winding oi relay 103 to vibrating contacts of armature 124 of relay 122. Relay 107 at its armature 112 completes the obvious circuit of relay 176 which again operates to short circuit the calling loop circuit to remove the 110- Volt current therefrom.

Relay 122 operates lwhen its second energizing circuit is closed by relay 107 and at its armature 124 starts the contact Vibrating. This contact finally cornes to rest and completes the circuit Vof relay 103 in parallel with that or relay 122 by Way of resting contact and armature 111 of relay 107. Relay 103 operates and at its armature 165 completes the circuit for relay 128 by Way of armature 109 and make contact, normally closed contacts controlled by armature 130 of relay 128, Winding of relay 128, resting contact and armature 167 of sleeve relay 165, and through the resistance to battery.

Relay operates and at its armature 129 and make contact completes the circuit of relay 132 from ground through resting contact and armature 140 or" relay 132. At its armature 131 relay 128 completes the circuit of the line lamp L, Fig. 3, over conductor 174.

Relay 132 operates when its circuit is closed, at its armature 134 and make contact connecting ground to release trunk conductor 44 and at the break contact of that armature, opening the circuit of relay 126, at armature 135 preparing a locking circuit for itself, at armature 136 opening the circuits of relays 176, 103, 107, 113, and 122, and at armature 137 disconnecting positive -volt current from conductor 45.

Relay 113 upon releasing after its circuit is opened, reconnects the relay 160 to the conductors 43 and 45, and relay 176 upon releasing, removes the short circuit from the calling loop by gradually increasing the resistance of the short circuit to the maximum presented by the carbon piles.

Relay 100 operates immediately when connected to the trunk and at armature 101 and make contact completes a locking circuit for relay 128 over armature 130 and make contact before sloW-to-release relay 128 has had time to release after opening its energizing circuit at the normally closed contacts of its armature 130. Engagement of armature 102 with its make contact has no effect on relay 122 at this `time since the circuit of this relay is opened at the normally closed contacts of armature 134 of relay 132.

In this condition of the equipment relays 100, 128, 132, and,147 are operated and the line lamp L, Fig. 3, is lighted in frontof the toll operator in whose position the trunk 169-175 terminates.

With reference to Fig. l, the operation of the paystation equipment at substation A, when the positive 11e-volt current is applied to the calling loop by relay 113 as described, will now be explained. The path of the positive 11G-volt current is as follows: conductor 45, bank contact 42 and wiper 39 of selector S, lower talking conductor of the selector and a Contact in the banks of wiper 39 of line switch LS, wiper 39, conductor 16, impulse contacts 32 of calling device C, copper-oxide valve 34, primary winding of induction-coil relay 17, normally closed contacts controlled by armature 26 of relay 17, transmitter T, switchhook contacts 1--2, conductor 15 through line switch LS, wiper 38, upper talking conductor through selector S, wiper 38 and bank Contact 40, and trunk conductor 43. It will be remembered that conductor 43 is connected to ground in the trunk circuit and the conductor 45 is connected to positive 11G-volt current source through the winding of relay 144.

Relay 17 operates by means of its primary winding in this circuit and immediately attracts its armatures, at its armature 20 opening the normally closed contacts and closing its make contact, thereby outing the transmitter T out of the line circuit and including the 6,000-ohn1 resistance and the S200-ohm holding winding in series withl the primary winding. By this means the relay 17 will remain operated as long as the 110-volt current flows. V.At itsY armature 18 and resting contact, relay 17 opens the circuit through e the receiver R, at the make Contact of this armature completes the circuit for the refund mag-r net 13, and at its armature 19 and resting contact opens a point in the circuit of the upper winding of relay 27. Since it has been assumed that a coin has been deposited, the coin contacts will be in their operated position. circuit of the refund magnet is as follows: positive 11G-volt current on conductor 16, conductor 31, coin contacts 6-5, winding of refund magnet 13, copper-oxide valve 35, make contact and armature 18 of relay 17, switchhook contacts 1 2,

and over line conductor 15 to ground. rRefund. magnet 13 operates in this circuit to refund the deposited coin and to restore the coin contacts by attracting its armature 14 to release the latch 11. Attraction of armature 14 closes the contacts of mercury switch M with noeifect at this time. Opening of the coin contacts opens the circuit of the refund magnet 13 and this magnet releases, allowing the automatic restoration of the coin apparatus.

When the 11G-volt current Vis cut off from the calling loop by the operation of relay 176 as described, the relay 17 restores and reconnects the transmitter T and receiver R to the line.

The inclusion of the 6060-011111 resistance and the 3200-ohm holding winding in series with the calling loop circuit increases the resistance of that Y circuit sufficiently to cause the release of the marginally adjusted relay 144, Fig. 2, after the circuit of the refund magnet 13 has been opened at the coin contacts, whichV relay upon releasing closes the circuit of relay 147 which energizes and locks itself up as described.

Since no reversal of current has occurred in the calling loop circuit, the relay 21 will not have energized and will be in the position in which it is shown.

From the foregoing it will be appreciated that each time a paystation extends a call to a toll Therefore, the

. ing` of the lamp L1 informs the toll operator operator and. a coin is deposited in the coin apparatus, the coin is automatically returned to the calling subscriber uponseizure of a toll operators incoming trunk by the application of positive 11G-volt current'to the normally positive side' of the paystation line and that the 110volt`current is applied tothe trunk and removed therefrom in such a manner as to avoid any disagreeable clicks or sounds in the receiver of the paystation.4

If no coin has been deposited, the coin contacts would not have been in an operated position andthe refund magnet 13 wouldA not haveA operated. The rest of the equipment wouldj function as described, however, in order toobtain the release ofrelay 144 andthe consequent operation of relay 147.

It will be remembered that by the operation of relay 128, Fig. 2, the circuit of the Aline lampL, Fig. 3, was completed overV conductor 174 )at armature 131 and make Contact of relay` 128. The'toll operator, noticing the lighted condition of the lamp L, answers'the call by inserting the yanswering plug P of hei-cord circuit O into the answering jack J. The cord circuit O has been shown in skeleton form only withV those partsl necessary for a complete understanding vof this invention, since this cord. circuit may be similar to those shown in the two 'U. S.. Patentsl Nos. 1,770,392 and 1,771,842, vissued to `Thomas F. Crocker on July 15, 1930,` and July29, 1930respectively.

This insertion of plug P in jack J completes the following circuit for the sleeve relay 165, Fig. 2: ground, lower 1000-ohm winding of relay,165, conductor 171, sleeve contacts of jack J and plug P,' sleeve conductor 202, right-hand `normally closed vcontacts of ringing key K3, spring 205 .of key K2 and its normally engaging contact, spring 208 of key K1 and its normally ,engaging'contaca andthrough supervisory lamp SL to exchange battery. yRelay 165 operates in this circuit and attracts its armatures 166 to 168, inclusive, thereby disconnecting relay 153 from conductor 169' at armature 166, disconnecting relay 161 from trunk conductor 172 at armature 168, and at armature 167 opening the circuit of relay 128, which relay deenergizes. The supervisory lamp SL fails to light in series with relay 165 because of the comparatively high resistance of the lower winding.

Upon'deenergizing,` relay 128 at its armature 131 and make contact opens the circuit of the line lamp L and at the resting contact of that armature completes lthe circuit of paystation lamp Ll by way of armature 152 and make contact of relay 147 and conductor 175 since,'it will be remembered, relay 147 operated and locked itself to the release trunk conductor 44 upon the restoration of relay 144. `This light- 135. that a paystation is calling. This lamp remains lighted as long as the connection is maintained, serving as a constant reminder to the toll Voperator. l

Additional results of the restoration of relay 128y are the opening of the energizingrcircuit of relay 132 at armature 129and the completion of a locking circuit for that relay whichv is traceable from ground, armature 101 and make Contact of relai,T 100, armature` and resting Contact ofrelay 128, make contact and armature 135 of relay 182, and winding of relay 132v to battery. V f A locking circuit for relay 132 is also completed over conductor and make Contact and 15G spring 200 of jack J, which were closed by the insertion of the plug in the jack. Therefore, it is evident that relay 132 will remain energized until the calling subscriber has hung up the receiver, thereby opening the loop circuitv of relay 100, and until the toll operator removes the plug from the jack.

The toll operator now converses with the call- 1 ing subscriber and after determining the descircuit. -key K2 negative 11G-volt current is connected tination of the desired call requests the subscriber to deposit the necessary coins for the call. The toll operator is apprised of the amount deposited in the Well-known manner and, if the amount is correct, proceeds to extend the call by inserting the plug P into the jack J and performing the things necessary depending on whether or not the system is an automatic telephone system or a manual telephone system.

kThe .depositing of the rst coin, if more than one is required for the call, causes the operation of the coin lever 10 which moves 'the latch 11 and consequently the coin contacts to the operated position. This prepares circuits for the collecting and refunding 'magnets which are 'later controlled by the operator.

The toll operator, after receiving the usual tone caused by the deposited coin, will momentarily operate the coin control key` K, thereby momentarily completing the following circuit: 'ground through contacts of key K, conductor 173, armature 151 and make contact of relay 147, and winding of relay 156 to battery. Relay 156 operates in this circuit and locks itvself through its armature 159 and make Vcontact to ground at make contact and armature 148 of relay 147. Relay 156 at its armatures 158 and 160 and make-before-break contact arrangements reverses the connection of the relay v100 to the line conductors 43 and 45 to reverse the flow of current over the calling loop. This reversal causes the operation of relay 21 at the paystation, as explained in connection with the local call, which relay mechanically locks itself in its operated position by releasing the armatures of relay 27. With relay 21 in its operated position, the deposited coins can be refunded only by a voluntary action on the part of the operator.v Relay 21 cannot operate as a buzzer in this case because, when the current reversal occurs, the coin contacts 9 and 8 are separated.

If the call'is successfully extended by the toll operator, she Will collect the deposited coins by the operation of collect key K2 of her cord At the make contact of spring 206 of to the ring conductor 203 of the cord circuit, at spring 204 and its make contact the tip conductor 201 is connected to ground, and by the v separation of spring 205 and its resting contact battery is disconnected from the sleeve conductor 202, thereby causing sleeve relay 165, Fig. 2, to restore and retractits armatures. At armature 168 and its resting contact they lower Winding of relay 161 is connected to the nega- 65'" tive 110-volt current over conductor 172, spring contacts of jack J and plug P, and conductor 203. Relay 161 thereupon operates, at its armature 162 and make contact locking itself to ground on tip conductor 201 over resting conductor and armature 166 of relay 165, trunk conductor 169, and tip contacts of jack J and plug P. At its armature 163 and make contact, relay 161 completes the obvious circuit of relay The negative 11n-volt current now flows and armature 168 of relay 165, armature 164 and make contact of relay 161, make contact and armature 137 of relay 132, make contact and armature 121 of relay 113, since this relay operated when its circuit was closed by relay 161, conductor 45, lower talking conductor through the selector S and line switch LS, and thence over the previously traced circuit of the primary winding of relay 17 to ground on conductor 43 supplied through armature 114 and make contact of relay 113. Relay 17 operates in this circuit as When positive 11G-volt current was applied to its winding, and at its armature 18 and make contact completes the following circuit for the collect magnet 12: negative 11G-volt current on conductor 16, conductor 31, coin contact 6--5, Winding of collect magnet 12, electronic valve 36, armature 18 and make contact of relay 17, and through hookswitch contacts 1 2, to ground on conductor 15. The collect magnet operates in this circuit to collect the deposited coin and release the coin contacts. The refund magnet 13 is prevented from receiving this negative 11G-volt current by the electronic valve 35.

In order to insure complete operation of the collect magnet 12, a circuit therefor, which is independent of the coin contacts, is completed when the magnet 12 attracts its armature and tilts'the mercury contact switch M. This circuit is as follows: negative 11o-volt current through the primary winding of relay 17, make contact and armature 20 thereof, armature 23 and make contact of relay 21, contacts of mer'- cury vswitch M closed by the mercury when the switch is tilted, and thence through the winding of collect magnet 12 to ground on conductor 15 over the previously traced circuit. Magnet 12, therefore, receives current as long as relay 17 remains operated, which is until the toll operator restores her collect key K2. Upon the restoration of key K2, the negative 11G-volt current is removed from the trunk and relay 17 restores, at its armature 18 and 20 reconnecting the receiver and transmitter to the line. Restoration of key K2 also resultsin the unlocking of relay 161 followed by the restoration of relay 113 and the reoperation of sleeve relay 165. Conversation betweenthe calling and called subscribers may nowtke place.

If the toll operator should be unsuccessful in extending the call, she will operate her refund key K1 to return the deposited coins to the calling subscriber. Operation of this key connects ground to the tip conductor 201, opens the sleeve j' conductor 202, and connects positive ll0-volt current to the ring conductor 203. Relays 165, 161, and 113 function the same as when key K2 was operated. Relay 17 functions the same as when positive 110-volt'current Was applied upon seizure of the trunk by the selector S and completes the circuit cf the refundmagnet 13 as previously described, Which magnet thereupon operates andv returns the deposited coins to the calling subscriber.

It is sometimes the practice for the toll operator to request the calling subscriber to hang up While she is extending the call. The only result of the replacement of the receiver R on the switchhook when this occurs is the restoration of relay 100 which causes the lighting of supervisory lamp SL of the cord circuit by completing the following circuit therefor: ground, armature 101 andv resting contact of relay 100, normally closed contacts controlled by armature 117 of relay 113, armature 141 and resting contact of relay 138, and through the upper 10-ohm winding of relay 165, and over the previously described circuit to the lamp SL and battery. The upper lO-ohm winding of relay 165 short circuits the lower winding of this relay, thereby permitting the supervisory lamp SL to light in a low resistance circuit to inform the operator that the calling subscriber has hung-up as requested. Relay 165 remains energized in series with the supervisory lamp SL.

The connection is maintained with the paystation since relay 132 remains locked upv to ground on conductor 170 from springs of jack J and maintains the holding ground for the selector S and line switch LS on the release trunk conductor 44 through its armature 134 and make contact and resting contact and armature 140 of relay 138. When the operator has extended the Vconnection or when she desires to inform theV calling subscriber that she is unable to extend the connection, she operates her ringing key K3 which opens sleeve conductor 282 to restore sleeve relay 165 and connects negative exchange battery to the tip conductor 201. Relay 153 of the trunk circuit thereupon operates from ground, winding of relay 153, resting contact and armature 162 of relay 161, resting contact and armature 166 of relay 165, conductor 169, tip contacts of jack J and plug P, and over tip conductor 201 v to negative battery supplied through the make contacts of ringing key K3.

Relay 153, upon operating, at its armature 155 and make contact connects ringing generator by way of resting contact and armature 121 of relay 131 to conductor 45 and thence over the lower talking conductor through the selector and line switch to the conductor 16, and through the ringer B and condenser to ground to signal the subscriber at the paystation. Restoration ci" the ringing key K3 causes the release of relay 153 and the reoperation of relay 165. The operator, upon the response of the party, either requests the depositing of coins or informs the party that she has been unsuccessful in extending the call.

It may happen that the toll operator, because of some abnormality, may request the calling subscriber to hang-up after the coins have been deposited and after relay 21 has operated following the momentary operation of key K, until she is ready to call back. When the switchhook springs are restored by the replacement or the receiver, the following circuit is completed: ground supplied through conductor 16 through the upper winding oi' relay 100, conductor 31, coin contacts 6 5, resting contact and armature 30 of relay 27, lower winding of relay 27, switchhook contacts 3 2, to battery supplied to conductor 15 through the lower winding of relay 100.` Relay 27 energizes in this circuit and at the commencement of the moving of its armatures opens the contacts 30, thereby interrupting its own circuit before'it has had time to completely attract its armature 28 release the relay 21. This opening of the circuit of relay 27 causes that relay to restore and at its armature 30 and resting contact again completes its circuit. Relay 27 ther^ fore repeatedly emergizes and deenergizes and by so doing generates a tone which is heard by the operator and which informs the operator that there are coins in the coin hopper to be either collected or refunded. If, after a time, the operator determines that the coins must be refunded, she rings the calling subscriber, as before eX- plained, by the operation of key K3. After the party has responded, the operator operates the refunded key K1 to refundthe coins as explained. Ringing the calling party in order to refund the coin is necessary because with relay 21 in operated position and with the hookswitch springs at normal, any application of 110-volt current, regardless of polarity, operates the collect magnet 12, since relay 17 cannot operate to operate the refund magnet because ofthe open vcondition of hookswitch contacts 1 2.

When the subscribers have completed their conversation after a successful connection, they replace their receivers upon the switchhooks. The replacement of the receiver at the paystation A causes the release of relay 16) and the lighting of the supervisory lamp SL as previously explained to provide the operator with disconnect supervision. The operator thereupon withdraws the plug P from the jack J and the plug P from the jack J Removal of plug P from jack J results in the removal of ground from conductor 170 at jack contacts 200 and the removal of battery from the sleeve conductor 171. Relay 165 restores when the battery is removed from conductor 171 but relay 132 remains operated in the following circuit after the ground is disconnected from conductor 170 at the jack: ground, make contact and armatureV 150 of relay 147,` resting contact and armature 142 of relay 138, lower winding of slowrelease relay 138, conductor 170, make contact and armature 135A of relay 132, and winding of relay 132 to battery. Relay 138 operates in this circuit and locks itself to ground at resting contact and armature 101 of relay 100 by way of its own make contact and armature 141. Other resuits of the operation of relay 138 are the completion of the obvious circuit of relay 113 at make contact and armature 143, the opening or" the circuit of Vits lower winding and consequently the circuit of relay 132 at armature 142, the removal of ground from the releasetrunk conductor 44 at armature 140, and at armature y139 the application of another ground connection to the release trunk conductor 44.

Relay 113 operates, whenits circuit is cornpleted, at armature 116 and make contact makes an additional ground connection to the release trunk conductor 44, at armature 114 and make contact connects trunk conductor 43 to ground, at armature 117 opens the locking circuit of relay 138 and at the make contact of that armature prepares another locking circuit for that relay, and at armature 121 and make contact connects trunk conductor 45 to the armature 137 of relay Relay 132 restores when its circuitis opened by relay 138 and at armature 137 and resting con-v tact connects positive 110-Volt current *throughV relay 144 and through make contact and armature 121 of relay 113 to trunk conductor 45 and consequently through the selector and liney switch to conductor 16. Since relay 21 is mechanically locked in its operated position and since the receiver at this time is on the hook, the positive 110-volt current operates the collect magnet 12 in the following circuit: ductor 16, conductor 31, coin contacts 6 5, winding of collect magnetr12, make contact and armature 26 of relay 21, resting contact and ar- L mature 19 of relay 17, electronic valve 37, hookswitch contacts 3 2, and conductor 15 to ground onv conductor 43. Relay 144 and collect magnet 12 operate on this flow of 110-volt current.

Relay 144 at its armature 146 completes a lockl coning circuit for slow-to-release relay 138 before that relay has had time to energize after its circuit was opened at armature 117 of relay 113. Collect magnet 12 operates to collect the coins in the hopper and to restore the coin contacts. Restoration of coin contact 6 into engagement with contact 7 completes the following circuit: positive 11G-volt current on conductor 16, conductor 31, coin contacts 6 5, armature 24 and make contact of relay 2l, upper Winding of relay 27, electronic valve 37, hookswitch contacts 4 3, and thence over conductor 16 to ground on conductor 43. Relay 27 operates in this circuit and mechanically unlocks relay 21 which, upon releasing, opens the circuit of relay 27. The opening of this circuit causes relay 144 to restore and at its armature 146 open the locking circuit of relay 13S. Relay 138 thereupon restores and releases relay 113 which in turn restores.

Restoration of relays 138 and 113 removes all ground connections from the release trunk conductor 44, thereby causing the restoration of the selector S and the line switch LS in the wellknown manner.

This application of positive 11G-volt current upon the release of the connection by both the calling party and the toll operator is a safeguard for the collection of coins in case the toll operator should have neglected to operate her collect key K3 after having received the usual tone caused by the depositing of the coinat the paystation.

If the coins had previously been collected by the operator in the way described, the application of positive 11G-volt current upon the termination of the connection would have merely operated the relay 27 to release the relay 21, since coin Contact 6 would have been in engagement with Contact 7 instead of contact 5.

From this description of the establishment of a toll connection from the paystation A, it has been seen that the application of positive l10- volt current to the normally positive side of the calling line when the receiver is off the hook at the paystation results in the refunding of any deposited coin, that the application of negaY tive 11G-volt current to the normally positive side of the line under the same conditions results in the collection of the deposited coin, and that the application of 'positive 11G-volt current to the same side of the line after the calling subscriber at paystation A has replaced the receiver on the switchhook results in the collection of any deposited coin. It has also been seen that after the current in the calling loop circuit has been reversed by the toll operator no refunding of coins can take place except by deliberate action on the part of the operator.` It has also been seen that means has been provided whereby, should an operator fail to collect coins in the usual manner, these coins are automatically collected whengthe connection is broken down and therefore are not left in the hopper to be automatically refunded in the manner described when a succeeding call is extended-to a toll operator. It has also been seen that the operations of the collect magnet l2 and refund magnet .13 by the application of various polarities of 1l0-volt current to the same side of the line are selectively controlled because of the direction of the current iiow as governed by the copper oxide valves.

When the subscriber at the regular or local station A desires to make a toll call,` he will take down his receiver, whereupon the line switch LS1 individual to the station A' will select a trunk leading to an idle selector such as S1. In response to the operation of the calling device Cl in accordance with the appropriate number to obtain connection with the toll operator, the selector S1 operates in the well-known manner tovselect an idle outgoing trunk to an operators position. It will be assumed that the idle trunk selected by the selector S1 is that comprising conductors 43 to 45, inclusive, Which terminates in the bank of the selector S1 at bank contacts 40' to 42', inclusive. When this trunk is seized by the selector S1, the relay 100 in the trunk circuit operates and the equipment in Fig. 2 thereupon functions as described to send the pulse of 11G-volt current over the calling line. This functioning of the trunk circuit at this time is without effect as far as the local station A is concerned, since it is not provided with any coin-collecting apparatus, and results only in the lighting of the line lamp L at the operators position.

It is to be noted in this type of a call that since the station A is not provided with paystation apparatus the resistance of the line is not noticeably increased when application of 11G-volt current takes place. Therefore, the relay 144 will remain energized as long as 11G-volt current remains on the line, thereby maintaining the circuit of relay 147 open at armature 145 of relay 144 until this circuit has been opened at armature 115 of relay 113 when the 11G-volt current is disconnected from the line. Therefore, relay 147 will not be operated at any time in this connection and when relay 128 is restored to normal upon the answering of the call by the operator, as described, the circuit ofthe paystation lamp L1 will not be completed. By this means, the toll operator will know that the call is being extended from a local station and that there will be no need for her to perform any coin-controlling operation.

Since in this case relay 147 is in the deenergized position when the connection is taken down by the toll operator, no operation of the relay 138 takes place, inasmuch as the circuit of its lower winding is open at armature 150 of relay 147 and consequently the relay 138 cannot operate and operate the relay 113 to send a pulse of positive 11G-volt current to the calling line.

It will be noted that the signalling bells at the local station A are bridged across the line when the receiver is on the switchhook. Under these conditions, operation of the ringing key K3 in the operators cord circuit, when she desires to ring the station A after having requested the subscriber thereat to hang-up, operates the relay 153 of the trunk circuit as before. This time, however, instead of ringing over the negative side of the calling line to ground at the substation through the bells and a condenser, the ringing circuit extends over the normally negative line conductor 15 back to ground over co``n ductor 43, armature 114 and resting contact of relay 113, armature 154 and make contact of relay 153, and resting contact and armature 148 of relay 147. A

With the few exceptions just noted, the operation of the trunk circuit is the same for both calls from paystations and calls from local stations, and it can be seen from this that the amount of equipment required in an automatic exchange employing such a trunk circuit is materially reduced, since it is unnecessary to provide diiierent groups of trunks for paystations and local stations.

The invention having been thus described, what is considered new and what it is desired to have protected by Letters Patent will be evident from the claims which follow.

What is claimed is:

l. In a telephone system, a station having coin collectine apparatus, a trunk circuit, an automatic switch controllable from said station to seize said trunk to extend a call, and means associated with said trunl; circuit and responsive to the seizure thereof by said switch for operating said apparatus to reiund any coin deposited therein.

In a telephone system, a paystation provided with coin collecting and refunding apparatus, an operators position provided with a linl; circuit for extending calls, a trunk circuit terminating at said position, an automatic switch controllable from said substation for seizing said trunk to extend acall to said position, means in said trunk circuit and responsive to the seizure thereof by said switch for signalling said position and for operating said apparatus to refund any deposited coin, said link circuit thereupon being connected to said trunk to extend the call beyond said position, and means responsive to the disconnection or" said link and trunk circuitsrwhen the call is terminated for operating said apparatus to collect any deposited coins.

3. In a telephone system, a paystation provided with a coin collector, a trunk circuit terminating in an operators position, a source of special current associated with said trunk circuit, an automatic switch controllable from said paystation to seize said trunk circuit to extend a call tc said position, and means in said trunk circuit responsive to the seizure of said trunk for momentarily applying said special current thereto to operate said collector to refund a deposited coin.

Ll. In a telephone system, a paystation provided with a coin collector, an operators position provided with a link circuit for extending calls etlirough, a trunk circuit terminating at said tion, automatic switch controllable from station, after the receiver thereat has been reino-ved from the receiver hook, to seize said trunk circuit to extend a call to said position, a source or special current associated with said trunk circuit, means in said trunk circuit responsive to the seizure thereof for signalling said position for momentarily applying said special current thereto to operate said collector to refund a deposited coin, said link circuit thereafter being connected to said trunk circuit to extend the call, and means in said trunk circuit responsive to the disconnection thereof from said linl; circuit after the call has been terminated for again momentarily applying said special current to the trunk to operate said collector to collect coins deposited after said refunding has taken place.

In a telephone system, a calling line provided with a coin collector at the substation of the line. a ti nk circuit terminating in an operators source of special current associated trunlf; circuit, means controllable over for connecting said line to said trunk o a call to said position, andmeans trirk circuit responsive to such connection grael l1' 'applying said special current to in said ier rent therefrom, said coin collectoroperated by the special current to refund a deposited coin.V

6. In a telephone system, a calling line provided with a coin collector, a trunk circuit terminating in an operators positoin a source ci special current associated with the trunk circuit, means controllable over said line connecting the line to the trunk. circuit to extend a call to said position, and operating automatically responsive to such connection for gradually short circuiting said line, connecting said special current to said trunlr. circuit, gradually removing s d short circuit to apply. said current to said line, again Y to remove said circuit therefrom, disconnecting said current from said trunk circuit, and again removing said bei." circuit from said line, said coin collector operated by said special current when applied to said line to refund a deposited coin. l 7. In a telephone system, a calling line having a coin collector, a trunk circuit terminating in an operators position, a source of special current associated with said trunk, means operable from the substation on said line for connecting said line to said trunk to extend a call to said position, a high resistance bridge circuit connected across the line end of said trunk, means responsive to the connection of said line to said trunk for decreasing the resistance `of said bridge circuit to short circuit the line, means for then connecting said special current to said trunk and causing said second means to gradually increase the resistance of said bridge circuit to gradually apply said special current to said line, said coin collector operated by said current on said line to refund a deposited coin.

8. In a telephone system, a calling line having .ly short circuiting said line a coin collector, a trunl; circuit terminating in an operators position, a source oi special current associated with said trunk, means controlled Y from said calling line for connecting said line to said trunk, a high resistance bridge circuit across said trunk including a series of non-compressed carbon discs, a relay in said trunk circuit adapted when operated to compress said discs to decrease the resistance of said bridge circuit and adapt-ed to release slowly to gradually remove the pressure iroin discs to gradually increase the resistance of bridge circuit, the line end of said trunk circuit being short circuited when the to the connection or" said line to said trunk to momentarily operate said relay to short circuit said line and then connect said special current to `.said trunk, said relay releasing slowly after the momentary operation and gradually increasing the resistance of said bridge circuit, thereby gradually removing said short circuit to gradually apply s id current to said' line, said coin collector thereupon operating to refund a deposited coin.

9. In a telephone system, a calling line, a trunk circuit, a source oi special current associated with said trunk, means for connecting the line to the trunk, a high resistance bridge circuit across the line end of said trunk, a relay in said trunk operated responsive to the connection of the line to the trunk, means responsive to the operation of said relay for decreasing the resistance of said bridge circuit to short circuit said line, and means also responsive to the operation of said relay for connecting said special current to said trunk and slowly releasing the second-mentioned means to gradually increase the resistance of said bridge circuitv to gradually remove the short circuit of said line, thereby gradually applying said special current to said line.

10. In a telephone system, a calling line, a trunk circuit, a source of special current associated with said trunk, means for connecting said line to said trunk, a normally high resistance bridge circuit across the line end of said trunk, a relay in said trunk operated responsive to the connection of said line to said trunk, means esponsive to the operation of said relay for gradually decreasing the resistance of said bridge until said line is shortcircuited, means also responsive to the operation of said relay for connecting said special current to said trunk and controlling said second-mentioned means to gradually increase the resistance of said bridge circuit, thereby gradually removing the short circuit of said line to gradually apply said special current thereto, and means for thereafter controlling said secondmentioned means to again gradually and momentarily short circuit said line to remove said special current therefrom and disconnect said specialcurrent from said trunk while said line is momentarily short circuited.

1l. In a telephone system, a calling line having a substation provided with coin collecting and refunding apparatus, a trunk circuit terminating in an operators position having a link circuit for extending a call therethrough, a source of special current of positive and negative polarities, means for connecting said line to said trunk to extend a call to said position, means in said trunk responsive to the connection of the line thereto for connecting the special current of positive polarity to the normally positive side of said line, whereby said coin collector is operated to refund a deposited coin, means for connecting said link circuit to said trunk, means in said link circuit for applying said special current of either polarity through said trunk to the same side of said line, whereby said coin collector is operated when the current of the negativerpolarity is applied to collect any deposited coins or is operated when the current of positive polarity is applied to refund deposited coins, and means operating automatically when said link is disconnected from said trunk after the call is terminated by said substation to again apply the special current of positive polarity to the same side of said line, whereby said coin collector is operated` if any coins are therein to collect those coins.

12. In a telephone system, a calling line, a coin collector at the substation ci' said line having a collect magnet and a refund magnet, a trunk circuit terminating in operators position having a link circuit for extending a call therethrough, a source of special current of positive Yand negative polarities, means forrconnecting said calling line to said trunk to extend a call from said line to said position, means in said trunk responsive to such connection for momentarily connecting the special current of positive polarity to said trunk and to said line and for signalling said position, Vmeans at said suostation for directing said positive polarity current through said refund magnet to operate magnet to reund a deposited coin, and means in said link circuit effective after said link has been connected to said trunk to extend the call through said position for applying at will either of said polarities of the special lcurrent to said trunk and line, said means at said substation directing the special current of negative polarity through the winding of the: collect magnet 'to collect coins deposited at the request of the operator or directing the special current of positive polarity through the Winding of the refund magnet torrefund such coins.

'13. In a telephone system, a calling line, a coin collector at the substantion of said line having a collect magnet and a refund magnet, a trunk circuit terminating in an operators position having a link circuit for extending calls therethrougha source of special current of positive and negative polarities, means for connecting said calling line to said trunk circuit 'to extend a call to said position, means in said trunk operating automatically responsive to that connection to momentarily apply the special current of positive polarity to said line, and means in said link circuit effective after said link circuit is connected to said trunk for applying at will the special ctnrent of either polarity over said trunk to said line, and circuit means including electronic valves at said substation for directing the now of said special current of positive polarity throughthe refund magnet and that of negative polarity through the c llect magnet.

14. In a telephone system, a paystation line, a coin collector at the paystation having a collect magnet and a refund magnet, a local line, a trunkcircuit terminating in an operators position having a link circuit for extending calls therethrough, a source of special current associated with said trunk circuit, means for connecting either of said lines to said trunk circuit to extend a call to said position, means in said trunk operating automatically responsive to the ccnnection of a calling line thereto to momentarily apply said speci-.al current to that line, circuit means at the paystation effective when the paystation line 's the calling line for directing.,r said special current through the Winding of said refund magnet to refund a deposited coin, and means in said trunk circuit operating automatically upon the disconnection of said link` circuit from said trunk upon the termination of a call by the calling station for momentarily applying said special current to the calling line only when the calling line is said paystation line, said circuit rneans at said paystation under these conditions directing the special current through the winding of the collect magnet to collect coins deposited at the request of the operator.

15. In a telephone paystation apparatus, a coin collector having a collect magnet and a refundV magnet, contact springs controlled by the receiver hook of the telephone, and circuit connections for said magnets including said contact springs, wherebyoperating current of a positive polarity applied to said connections operates the refund magnet to refund a deposited coin when the receiver is off the hook and operates the collect magnet to collect a deposited coin when the receiver is on the hook.

l5. In a telephone paystation' apparatus, a coin collector having a collect magnet and a refund magnet, contact springs controlled by the receiver hook of the telephone, current now directing devices, and circuit connections for said magnets including said contacts and said devices, whereby operating current of one polarityapplied to said connections is .irected to operate the refund magnet when the receiver is oil the hook and to operate the collect magnet when the receiver is on the hook.

1'?. In a telephone paystation apparatus, a coin collector having a collect magnet and a refund magnet, contact springs associated with said collector and moved to an operated position by a for connecting said link circuit to said trunk to answer said call, means at said paystation operated over the calling line and trunk by the toll operator after coins have been deposited in the collector at her request for preventing operation of the coin collector to refund the deposited coins except at her direction, this means mechanically locking itself operated upon being operated by the toll operator, operator controlled means in said link circuit for connecting the special current of either polarity to said trunk and calling line, whereby te toll operator can control said coin collector to collect or refund at will, and means in said trunk circuit responsive to the disconnection of the link circuit from the trunk circuit after the call has been` terminated at the pay-` station for momentarily connecting the special current of positive polarity to said trunk and line, and means at the paystation operated by this momentary connection of special current Vto restore said mechanically locked means.

25. In a toll service telephone system, a calling paystation line having a coin collector` at the paystation, a toll operators position, circuit means for connecting said line to said position to extend -a call thereto, means at said position for controllingl said coin collector to collect or refund coins deposited at the operators request, and means at the paystation operating automatically upon the termination of the connection by the paystation when there are coins in said collector to signal the operator that there are coins in the collector.

26. In a toll Yservice telephone system, a calling paystation line having a coin collector, a toll operators position, circuit means for connecting the calling line to the operators position to extend a call thereto, and means at the paystation operating automatically upon the replacement of the receiver at the paystation when there are coins in the collector to'be disposed of to audibly signal the operator to that effect.

27. In a toll service telephone system, a calling line, a substation on said line having paystation apparatus, a trunk circuit terminating in an operators position provided with a link circuit, means controlled from said substation for connecting said line to said trunk circuit to extend a call to said position, whereuponv the operator connects said link circuit to said trunk circuit to extend said call through said position, means responsive to the connection of said line to said trunk circuit for transmitting a first impulse of current over said line, circuit connections at the substation whereby said iirst impulse of current operates said apparatus to refund a deposited coin, means whereby the operator manipulates said circuit connections to cause a second impulse of current to operate the apparatus to collect a coin deposited at her request, and means responsive to the disconnection of said link circuit from said trunk circuit for transmitting a third impulse of current over said line.

28. In a toll service telephone system, a calling line having paystation apparatus, a trunk circuit terminating in an operators position, means controlled from the substation of said line for connecting said line to said trunk circuit to extend a call to said position, means in said trunk circuit responsive to the connection of said line thereto for operating said paystation apparatus to refund a deposited coin, and means whereby the operator renders said apparatus unoperable to refund any coins deposited at her request except under her control.

29. In a telephone paystation apparatus, a coin collector having a collect magnet Yand a refund magnet, contact springs controlled by the receiver hook of the telephone, and circuit connections for said magnets including said contact springs whereby operating current applied to said connections operates said refund magnet when the receiver is oif the hook to refund a deposited coin and operates the collect magnet when the receiver is on the hook to collect a -deposited coin.

30. Telephone pay'station apparatus for use in an automatic telephone system wherein the final switch in the switch train reversesnthe normal flow of exchange current over the calling line upon response of the called party, said 'apparatus comprising a coin collector having a refund magnet and a collect magnet, contacts controlled by the receiver hook of the'telephone, a relay responsive to the reversal of the normal current ilow, and circuit connections for said magnets controlled by said relay and completed by said contacts upon the replacement of the receiver on the hook wherebythe normal current flow operates the refund magnet to refund a deposited coin upon termination of an incomplete connection and operates the collect magnet to collect a ideposited coin upon termination of a completed connection.

31. Telephone paystation apparatus for use in an automatic telephone system wherein the iinal switch in the switch train reverses the normal flow of exchange current over the calling line upon completion of a connection by the called party and restores thenormal current flow upon termination of the connection by the called party, said apparatus comprising a coin collector having a collect magnet and a refund magnet, a relay having an armature with a break contact and a make contact, a current flow directing device, circuit connections for said relay including said device whereby said relay is operatively energized by the exchange current when the normal flow thereof has been reversed, contacts controlled by the receiver hook of the telephone, circuit connections for the refund magnet including said receiver hook contacts and the armature and break contact of said relay whereby the normal flow of exchange current operates said refund magnet to refund a deposited coin upon the termination of an incomplete connection, and circuit connections for the collect magnet including said receiver hook contacts and said armature and make contact whereby the normal iiow of exchange current operates said collect magnet to collect a deposited coin upon the termination of a completed connection.

32. In a telephone system, a calling line terminating in an exchange having a central source of current, a toll device on said line, a trunk circuit, a source of current other than said central source associated with said trunk circuit, means operated by current from said central source and controlled from the substation of said line for connecting said line to said trunk circuit, and means in said trunk circuit operated by current from said central source responsive to said connection for momentarily applying said special current to said line to operate said device.

33. In a telephone system, a calling line having a toll device and terminating in an exchange having a central source of current, a trunk circuit for extending calls, a sourcev of special current other than said central source associated with said trunk circuit, means controlled by said calling line for connecting said line to said trunk circuit, whereupon a current flow from said central source is established over the talking strands of the connection including the line and trunk circuit, means operatingautomatically responsive to said establishing of the current oW for momentarily interrupting that current oW and momentarily establishing a now of said special current over the talking strands to operate said measured service device.

34. ln a telephone system, a paystation line, a regular subscribers line, a trunk circuit terminating in an operators position, a source of special current associated with said trunk circuit, means controlled from the substation of either line for connecting either line to said trunk circuit to extend a call to said position, means in said trunk circuit responsive to the connection of either or said lines thereto for transmitting an impulse of said special current over the connected line and for signalling the operator to indicate the extension of a call thereto, and means at the substation of the paystation line operated by said impulse of special current When the paystation line is connected to said trunk circuit for conliay trolling said signalling means to indicate that the call is being extended over the paystation line.

35. In telephone sytem, a paystation line pro-A vided with coin collecting and refunding apparatus, a regular subscribers line, a trunk circuit terminating in an operators position, a source of special current associated with said trunk circuit, means controlled from the substation of either line for connecting either line to said trunk circuit, means in sai-d trunk circuit responsive to the connection of either line thereto for transmitting an impulse of said special current over the connected'line and for signalling the operator that one of said lines has extended a call to said position, said apparatus responsive to said impulse of special current when said paystation line is connected to said trunk circuit for refunding a deposited coin, and means associated with said apparatus and responsive therewith to said impulse for controlling said signalling means v to indicate at said position that the paystation line is the calling line. Y

CHARLES R. BROOKS. 

